In general, it is possible to process, singulate and embed a semiconductor chip (also referred to as integrated circuit, IC, chip or microchip) using semiconductor technology on and/or in a wafer (or a substrate or a carrier). A finished produced chip (e.g. an embedded integrated circuit) can be mounted in or on a carrier and contacted in order to provide a specific functionality, such as e.g. the switching of electric currents. In order to reduce resistive losses of the chip, which reduces the power consumption thereof, particularly in the case of high electric currents, the chip overall can be produced so as to be as thin as possible, such that a vertical current path through the chip is as short as possible. In order to produce such chips, correspondingly thin wafers are required, e.g. for producing metal oxide semiconductor field effect transistors (MOSFETs), insulated-gate bipolar transistors (also referred to as IGBT) or emitter controlled diodes (also referred to as Emcon diode).
The processing of correspondingly thin wafers can constitute a particular challenge since said wafers are very sensitive and not mechanically loadable. It is conventional practice, therefore, to mechanically stiffen a thin wafer in order to counteract damage to the thin wafer as a result of the deformation thereof. The stiffening of the thin wafer can become necessary, for example, while the rear side thereof is thinned to the desired thickness. Likewise, other processes, such as transporting the wafer or cleaning the wafer, for example, can necessitate stiffening.
It is conventional practice, for stiffening the wafer, to selectively grind away the rear side thereof, such that the edge of the wafer remains (e.g. also referred to as rear-side support ring) which surrounds the thinned region of the wafer. Alternatively or additionally, during thinning or after thinning, the wafer is adhesively bonded by its front side onto a planar carrier, which together form an adhesively bonded laminate.
However, preventing the adhesive used for adhesively bonding the front side of the wafer from coming into direct contact with the electronic circuits is possibly only with great effort. Therefore, it is conventional practice to use an adhesive which can easily be released again, such that damage to the electronic circuits situated on the front side of the wafer is avoided as much as possible. Nevertheless, wetting of the front side with the adhesive cannot be avoided, and even easily releasable adhesives can be removed without residues only with considerable effort. This is achieved by means of polymer-based adhesives, but they restrict the temperatures to which the adhesively bonded laminate can be subjected (e.g. to less than 200° C.). Easily rereleasable adhesives likewise increase the risk of the laminate detaching prematurely.
The adhesively bonded laminate makes the chemical mechanical polishing of the rear side of the wafer more difficult or makes it essentially impossible. In particular, the non-planar rear side of the laminate makes the further processing thereof more difficult and necessitates further adaptations, e.g. if a wafer chuck is intended to be used.